Configuring a Line Clock Source
Context
To implement clock synchronization on a switch, configure a clock source first. When a switch needs to restore time signals through Ethernet code streams received by Ethernet interfaces, the switch must be configured to trace a line clock source.
Clock source priority
The default priority for a clock source is 0, indicating that this clock source does not participate in clock source selection. To enable the clock source to participate in clock source selection, specify a priority for it.
A lower priority value indicates a higher priority of a clock source.
Clock source SSM quality level
An SSM is a group of codes used to indicate the clock quality level on a synchronized network. SSM reflects the level of synchronous timing signals transmitted on a synchronous timing link. A higher clock accuracy indicates a higher SSM quality level. A device can be configured to select a clock source according to the SSM quality level.
SSM quality levels are sorted in descending order of preference: primary reference clock (PRC), Synchronization Supply Unit A (SSU-A), Synchronization Supply Unit B (SSU-B), SDH equipment clock (SEC), Unknown, and Do Not Use (DNU).
Procedure
- Run system-view
The system view is displayed.
- Run clock ethernet-synchronization enable
The synchronous Ethernet function is enabled.
By default, the synchronous Ethernet function is not enabled.
- Run interface interface-type interface-number
The view of the interface on which the line clock source resides is displayed.
- Run clock synchronization enable
The clock synchronization function is enabled.
By default, the clock synchronization function is not enabled for a line clock source.
- Run clock priority priority-value
A priority is configured for the line clock source.
By default, the priority of a line clock source is 0, indicating that the clock source does not participate in clock source selection. A smaller priority value indicates a higher priority.
- (Optional) Run clock ssm { unk | prc | ssua | ssub | sec | dnu }
An SSM quality level is configured for the line clock source.
By default, the SSM quality level of a line clock source is sent from the peer device.